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91.
Deniz Bingöl Salih Aydoğan Seda Karayünlü Bozbaş 《Metallurgical and Materials Transactions B》2012,43(5):1214-1219
The wet mechanochemical process was optimized for insoluble SrCO3 and soluble (NH4)2SO4 formation from celestite (SrSO4)-(NH4)2CO3-H2O mixtures in a planetary ball mill by Box-Behnken design (BBD). The products formed during wet milling were analyzed with scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared (FT-IR) spectroscopy. For converting to SrCO3 of celestite (SrSO4) and to (NH4)2SO4 of (NH4)2CO3, a hydrometallurgical process optimization via the wet mechanochemical conversion using (NH4)2CO3 was developed the first time in this work using response surface methodology. The wet mechanochemical conversion was carried out by varying ball to grinding material mass ratio, (NH4)2CO3 to SrSO4 mole ratio and the rotational speed of mill in a planetary mill. Under the optimum experimental conditions (9.24 of ball to grinding material mass ratio, 1.86 of (NH4)2CO3 to SrSO4 mole ratio and 400 rpm of the rotational speed of mill), the conversion of SrCO3 was 99.08 pct. The (NH4)2SO4 obtained as byproduct was crystallized. 相似文献
92.
93.
Synthesis and characterization of soluble multi-walled carbon nanotube/poly(organophosphazene) composites 总被引:1,自引:0,他引:1
Poor solubility of carbon nanotubes (CNTs) in water and organic solvents offers a significant problem for their applications. Macromolecules can be suitable solubilizing agents and a structural component of composite materials for CNTs. Several polymers were tested for the preparation of CNT dispersions. In this study, a poly[(4-pyridineoxy)(phenoxy)phosphazene] (3) was prepared by sequential treatment of poly(dichlorophosphazene) (2) with sodium 4-pyridineoxy and sodium phenoxide in THF. Multi-walled carbon nanotube/poly(organophosphazene) composites (f-MWCNT/PZS) with different feed ratios [Rfeed = 1:1, 1:3, 1:5 and 1:10 (w/w)] were obtained by the treatment of the functionalized multi-walled carbon nanotube (f-MWCNT) with the protonated poly(organophosphazene) (PZS). Excellent dispersions of the f-MWCNT/PZS nanocomposites in water and common organic solvents were achieved. The influence of feed ratio on polymer coating and the stability of composites were investigated by thermal gravimetric analysis (TGA). f-MWCNT/PZS1:5 nanocomposite was characterized by 31P, 1H NMR, FTIR, XRD, EDX and Raman Spectroscopy. The morphologic characterizations of f-MWCNT/PZS1:5 were carried out by HRTEM and SEM methods. 相似文献
94.
Polymer Bulletin - In this work, novel polypropylene/BiSr2CaCu2O6.5 (PP/Bi-1212) thick film composites having ceramic content varying between 0.5% and 6% were prepared to enhance both the... 相似文献
95.
96.
Atas Müslüm Felfernig Alexander Polat-Erdeniz Seda Popescu Andrei Tran Thi Ngoc Trang Uta Mathias 《Journal of Intelligent Information Systems》2021,57(3):467-489
Journal of Intelligent Information Systems - User preferences are a crucial input needed by recommender systems to determine relevant items. In single-shot recommendation scenarios such as... 相似文献
97.
Engineering with Computers - Fractal–fractional differential and integral operators have been recognized recently as superior operators as they are able to depict physical problem with both... 相似文献
98.
Hilal Zeynep Sahin Mehtap Celik Seda Kotay 《Food Additives and Contaminants: Part B: Surveillance Communications》2016,9(2):152-158
This study aims to detect aflatoxins (AFs) in dairy cow feed, milk and milk products using a high-performance liquid chromatography coupled with fluorescence detection (HPLC-FLD) method. All the validation parameters met the method performance criteria of the European Union. The samples comprised 76 dairy cow feeds and 205 milk and milk products (including yoghurt and yoghurt-based beverage, ayran). AFs were present in 26.3% of the feed samples. Two feed samples exceeded the maximum limit (ML) of 5 µg kg?1 for AFB1 as established by the EU. Nineteen milk samples (21.1%) contained aflatoxin M1 (AFM1) of which three exceeded the EU ML of 0.05 µg l?1. In addition, only two yoghurt samples and one ayran sample contained AFM1, but the levels were lower than the EU ML. 相似文献
99.
Samira Fatma Kurtoğlu Seda Sarp Ceren Yılmaz Akkaya Barış Yağcı Amir Motallebzadeh Sezen Soyer-Uzun Alper Uzun 《International Journal of Hydrogen Energy》2018,43(21):9954-9968
Sepiolite, a clay mineral, was utilized as a support for nickel-based catalysts for COx-free hydrogen production from ammonia decomposition. First, the physical and chemical properties of sepiolite were changed by calcining it at temperatures varying from 500 to 1000 °C, then nickel was impregnated on these calcined supports and tested for ammonia decomposition at various temperatures following reduction at 650 °C. Results indicated that even though the catalysts contained almost the same amount of nickel, they showed different hydrogen production performance. Detailed characterization of the catalysts before and after reaction illustrated that the support obtained by calcining sepiolite at 700 °C shows good basic properties with a high surface area offering a high degree of nickel dispersion. These properties lead to promising hydrogen production rates which are on par, if not higher, than most of the nickel-based catalysts prepared on supports, which are either not cheap or require tedious preparation procedures. 相似文献
100.
The aim of this in vitro study was to compare the efficacies of two different fiber post‐removal systems. Thirty extracted single‐rooted mandibular premolar teeth were used. After RelyX fiber posts were cemented, the teeth were divided into two groups with regard to the post removal techniques: ultrasonic vibration and D.T. Light‐Post removal kit. Residual material, tooth volume changes, working time and micro‐crack formation were assessed using micro‐computed tomography. All data were analyzed using Wilcoxon signed‐rank and Mann–Whitney U tests. There was significantly more tooth root volume change in the ultrasonic group than removal kit group (p < .05). Fiber post removal time for the ultrasonic group was significantly longer than the removal kit group (p < .01). 相似文献